This research project is directed toward the examination of morphological alterations in the nervous system of animals in which experimental epilepsy has been produced in order to understand the causes and effects of epilepsy in man. The alumina cream animal epileptic model has been used because it results in chronic recurrent seizures which are more like epilepsy in man. From the study of changes in this experimental model it is proposed that alterations associated with ictal events will lead to common structural changes associated with epilepsy. Alterations of the ionic microenvironment of individual and groups of cells in normal and epileptic brain may provide a definitive basis for some of the structural changes already seen. The study of experimental seizures by several associated methods is proposed: 1) study by serial excisions, alumina-free epileptic animals for histological changes and definition of foci; 2) create new animal epileptic models to provide access to greater animal population for research; 3) alter the ionic microenvironment of cells by chronic local manipulation to study associated structural and electrical changes; 4) study the subcellular changes in membrane structure of astrocytes and neurons in epileptic foci by freeze-fracture and etching techniques; 5) compare morphological alterations of experimental animals to excised epileptic foci in man. BIBLIOGRAPHIC REFERENCES: Dunker, R.O. and Harris, A.B.: Extracellular Space Diffusion in Infant, Adult and Edematous Cortex. Neurology 27: 399, 1977. Jenkins, D.P., Ross, J.B.A. and Harris, A.B.: The Detection of Multiple N-terminal Amino Acid and Side Chain Reactive Groups in Horseradish Peroxidase by the Dansylation Reaction. Anatomical Record 187: 614, 1977.